• Bulletin of the Korean Chemical Society
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• 제32권12호
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• pp.4321-4326
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• 2011

A new series of heteroleptic cyclometalated iridium(III) complexes has been synthesized and characterized by absorption, emission and cyclic voltammetry studies: $(pqx)_2Ir(acac)$ (1), $(dmpqx)_2Ir(acac)$ (2) and $(dfpqx)_2Ir(acac)$ (3) where pqx=2-phenylquinoxalinate, dmpqx=2-(2,4-dimethoxyphenyl)quinoxalinate, dfpqx=2-(2,4-difluorophenyl) quinoxalinate and acac=acetylacetonate anion. The reaction of excess acetylacetone with ${\mu}$-chloride-bridged dimeric iridium complex, $[(C\^N)_2Ir({\mu}-Cl)]_2$, gives a complex 1 and an unusual hydridoiridium(III) complex, $(pqx)IrH(acac)_2$ (4). The complex 1, 2 and 3 show their emissions in an orangered region (${\lambda}_{PL,max}$ = 583-616 nm), and the emission maxima can be tuned by the change of substituent at phenyl ring of 2-phenylquinoxaline ligand. The phosphorescent line shape indicates that the emissions originate predominantly from $^3MLCT$ states with little admixture of ligand-based $^3({\pi}-{\pi}^*)$ excited states. The structures of complex 3 and 4 are additionally characterized by a single crystal X-ray diffraction method. The complex 3 shows a distorted octahedral geometry around iridium(III) metal ion. A strong trans influence of the phenyl ring is examined. In complex 4, there are two discrete molecules which are mirror images each other at the ratio of 1:1 in an unit cell. We propose that the phosphorescent complex 1, 2 and 3 are possible candidates for the phosphors in OLEDs applications.

• Bulletin of the Korean Chemical Society
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• 제32권1호
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• pp.122-126
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• 2011

A new phosphorescent cyclometalated heteroleptic iridium (III) complex with an ancillary ligand of 4-azacrownpicolinate was prepared and its metal ion selective phosphorescent chemosensing behavior was investigated. The new iridium (III) complex exhibits notable phosphorescence quenching for Hg2+ in aqueous 50% acetonitrile solution with respect to the selective phosphorescent detection of various metal ions including $Li^+,Na^+,K^+,Cs^+,Mg^{2+},Ca^{2+},Ba^{2+},Fe^{2+},Ni^{2+},Cu^{2+},Zn^{2+},Ag^+,Pb^{2+},Cd^{2+},Cr^{2+},Cr^{3+}$ and $Hg^{2+}$. The phosphorescence quenching for $Hg^{2+}$ increased linearly with increasing concentration of $Hg^{2+}$ in the range of $10{\mu}M-700{\mu}M$ even in the presence of other metal ions, except for $Cu^{2+}$. Consequently, the new iridium (III) complex has the potential to be utilized for the determination of parts per million levels of $Hg^{2+}$ in aqueous acetonitrile media.

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2007년도 7th International Meeting on Information Display 제7권1호
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• pp.702-705
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• 2007

New heteroleptic tris-cyclometalated iridium complex, $Ir(ppy)_2(dpq-5CH_3)$, was prepared, where ppy and $dpq-5CH_3$ represent phenylpyridine and 2(5'-methyl)- 4-diphenylquinoline, respectively. The heteroleptic iridium complex shows high luminescence efficiency by the intramolecular energy transfer from the energy absorbing ppy ligands to the luminescent $dpq-5CH_3$ ligand leading to a decrease on quenching or energy deactivation.

• Bulletin of the Korean Chemical Society
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• 제34권2호
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• pp.399-405
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• 2013

Two series of new green phosphorescent polymers bearing a bis(2-phenyl-pyridine)iridium(III)(dibenzoylmethane) [$(ppy)_2Irdbm$] complex were designed and synthesized. Poly-carbazole (PCbz) derivative or polyfluorene with pendant carbazole groups (PFCbz) were employed as host polymers for the iridium complex. The iridium complex monomer was copolymerized with the host monomers using varying monomer ratios via a Yamamoto coupling reaction. Efficient energy transfer from host to dopant unit was observed by increasing the ratio of the iridium guest in the copolymers. Electroluminescent devices with the configuration ITO/PEDOT:PSS/polymer/BmPyPB/LiF/Al were fabricated and characterized. The phosphorescent polymers composed of the iridium complex guest and polyfluorene with carbazole pendants as a host performed better than the polymers composed of the same guest and the main chain polycarbazole host. A maximum external quantum efficiency of 0.73%, a luminous efficiency of 1.21 cd/A, and a maximum luminance of 372 $cd/m^2$ were obtained from a device fabricated using one of the synthesized copolymers.

• 대한화학회지
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• 제19권5호
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• pp.343-350
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• 1975

염산수용액중에 존재하는 이리듐을 그 분자량 아민(Alamine 336)의 벤젠용액으로 추출한 바 20${\sim}$100${\mu}g$의 이리듐을 정량적으로 추출할 수 있음을 알았고 이때 이리듐 추출의 가능성에 관하여는 방사성 추적자(Ir-192)를 써서 확인하였다. 유기층에 추출된 화학종의 흡광도를 파장 322.5nm에서 측정한 결과 본 방법은 이리듐의 정량을 위한 미량분석법으로 사용할수 있음을 알았다. 이리듐이 아민층에 추출되는 메카니즘에 대한 설명을 시도하였다.

• Bulletin of the Korean Chemical Society
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• 제32권11호
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• pp.4125-4128
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• 2011

• Bulletin of the Korean Chemical Society
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• 제34권9호
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• pp.2609-2615
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• 2013

A series of fluorene-carbazole copolymers containing the pendant phosphor chromophore $Ir(absn)_2(acac)$ (absn: 2-(1-naphthyl)benzothiazole; acac: acetylacetone) were designed and synthesized via Yamamoto coupling. In the film state, these copolymers exhibited absorption and emission peaks at approximately 389 and 426 nm, respectively, which originated from the fluorene backbone. However, in electroluminescent (EL) devices, a significantly red-shifted emission at approximately 611 nm was observed, which was attributed to the pendant iridium(III) complex. Using these copolymers as a single emission layer, polymer light-emitting devices with ITO/PEDOT:PSS/polymer:DNTPD/TmPyPb/LiF/Al configurations exhibited a saturated red emission at 611 nm. The attached iridium(III) complex had a significant effect on the EL performance. A maximum luminous efficiency of 0.85 cd/A, maximum external quantum efficiency of 0.77, maximum power efficiency of 0.48 lm/W, and maximum luminance of 883 $cd/m^2$ were achieved from a device fabricated with the copolymer containing the iridium(III) complex in a 2% molar ratio.

• Bulletin of the Korean Chemical Society
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• 제13권6호
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• pp.627-631
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• 1992

The dihydrido iridium(Ⅲ) complex [$Ir(PPh_3)_2H_2(ac)_2$]$BF_4$ (ac=acetone) reacts with 2-phenylpyridine and 7,8-benzoquinoline to yield the C-H activated complexes [$Ir(PPh_3)_2$H(ac)(L)]$BF_4$ (L= phenylpyridine; 7,8-benzoquioline). The dihydrido iridium(Ⅲ) complex [$Ir(PPh_3)_2H_2(ac)_2$]$BF_4$ also reacts with triaklysilane via an oxidative addition reaction to yield the trihydrido iridium complexes [$Ir(PPh_3)_2H_3SiR_3$]$BF_4$ (R =Et and Ph). The structual configuration was studied by conventional spectroscopy.

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2008년도 International Meeting on Information Display
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• pp.469-472
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• 2008

New iridium complexes with 2-(3',5'-bis-trifluoromethylphenyl)-4-metoxypyridine [$(CF_3)_2ppyOMe$] were synthesized and characterized for blue phosphorescent materials. It was found that $Ir[(CF_3)_2ppyOMe]_2$(acac) gives blue emission at 471 nm with strong luminescence efficiency. We discuss the role played by electron withdrawing substituents and also how the ancillary ligand influences the emission peak.

• Bulletin of the Korean Chemical Society
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• 제33권10호
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• pp.3465-3468
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• 2012